The use of electro-dynamic loudspeakers or earpiece units in apparatus is common. Most electronic devices contain an electro dynamic loudspeaker or transducer configured to convert electrical signals into acoustic waves to be output and heard by the user of the apparatus. For example mobile or similar telephones can contain an integrated transducer sometimes called an integrated handsfree (IHF) transducer configured to operate as an earpiece for speech and also as a loudspeaker for hands free and audio signal playback.